1. Field of the Invention
This invention relates to chairs. The invention is in particular directed to a chair in accordance with the principles of “Inclusive Design”, namely one which addresses the needs of less able-bodied and encumbered users, while nonetheless also meeting the needs and expectations of all users, while at the same time not looking in any way “different” or “special”. The invention is especially directed to the provision of a chair that is at least easy to get out of, as far as possible irrespective of the health and physical abilities of the user, and preferably is also easy to sit into, again as far as possible for users of all capabilities.
2. Description of the Prior Art
A traditional chair which can in certain respects be regarded as facilitating sitting and rising actions by users is the familiar rocking chair, which may have curved members engaging directly on the surface of a floor, or may have more complex arrangements involving a base structure, in order to achieve the required rocking feature, for example by a suspended structure or by curved members rocking on a fixed base.
A type of chair which is specifically targeted at the older or disabled user is the so-called “assist chair”, which may incorporate features such as an inflatable cushion or cushion portion, to elevate the user wishing to get out of the chair into a disposition in which returning to a standing position from a sitting posture is facilitated.
Users facilitated by such a function include not only those suffering from a specific physical disability, but also for example pregnant women, a breast-feeding mother, or anyone holding for example a child while sitting into or rising from a chair; in other words, any person who can be regarded as encumbered in the short term.
Prior art patent specifications relevant to the field of the invention include inter alia the following:
CA-A-2083642 describes a geriatric chair providing easy patient entry and exit and a stable-restraint-free environment for a patient seated in the chair and left unattended. The chair has a floor-engaging central fulcrum, such as for example a pair of wheels or rollers, and floor-engaging rest portions, respectively forward of and to the rear of the fulcrum. When the chair is tilted forward about the fulcrum, the front floor-engaging rest portion engages the floor, so that the seat of the chair is inclined downwardly towards the front and it is easy for the patient to get in. The chair can then be tilted rearwardly until the rear floor-engaging rest portion encounters the floor, in which orientation the centre of gravity of patient and chair is to the rear of the fulcrum, with the seat sloping downwardly towards the rear. However, by no stretch of the imagination can this chair be described as anything other than “different” and “special”.
EP-A-0775457 describes a chair having variable geometry, in which front and rear legs are linked by a front-to-rear member underlying the seat and pivoted to the front and rear legs such that the elongate extent of the cross-member between its pivot points with the legs is greater that the spacing between points at which the overlying seat is pivoted to the legs. A trapezoidal linkage is thus defined such that by pivoting the legs of the chair to the rear relative to the floor on which the chair stands, the seat is tilted downwardly towards the front, while pivoting the legs to the front causes the front of the seat to rise so that the seat then slopes downwardly towards the rear. The unit is called a “rocking chair”.
WO-A-0135798 describes a chair in which the seat may move backwards and forwards according as a person sitting on the chair leans against the backrest of the chair or leans forwards.
U.S. Pat. No.5,695,244 describes a rocking chair of more conventional aspect, in which the seat is supported by two spaced apart side members having a continuous outer periphery, each member having a large ground-contacting arcuate region that extends forwards and upwards and turns back and overlies the ground-contacting region of the members to form armrests. The relationship between the seat and curvature of the arcuate regions is selected so that the axis of curvature of the arcuate ground-engaging region is slightly rearward of the centre of gravity of an occupied chair, thus enabling the user to change the position of the chair over a wide range of orientations.
Resilient chair structures in which a single length of material, for example a metal tube or bar, is bent into a shape having a floor-engaging elongate portion and a seat supporting portion which are interconnected by a single upright portion of the bent material, are described by U.S. Pat. No. 2,981,315 and GB-A-374342. The basic shape of the chair frame may be generally that of a U turned on its side. Armrests may be provided by a further upstanding tube portion extending upwards from the seat supporting portion and further bent around to define a generally horizontally extending armrest portion.
A development of this type of structure is described in GB-A-416758, in which the generally horizontal floor-engaging portion and the seat supporting portion are further interconnected by springy members, typically of curved configuration, with the concavity of the curve opening in the same direction as the sideways oriented U-structure. This arrangement facilitates construction of the chair from less strongly resilient materials than are required for the structures of the aforementioned U.S. Pat. No. 2,981,315 and GB-A-374342.
Examples of laminated wood products adapted to comprise springiness or to provide parts of spring structures formed from such products are described in, inter alia, the following patent specifications:
AT-B-405783 describes a spring element for furniture, in particular a couch, in which upper and lower cambered laminated wood springs are arranged so that the concave faces of the elements face one another. A two-element wood spring is also described by JP-A-2006149948 in which a similar function is achieved by two laminated wood strips which are curved gently upwardly and cross one another intermediate their ends, so that one end of each element overlies an end of the other element. Each lower end can be fixed to a structure, and a load may be supported resiliently on the upper ends.
FR-A-2582980 describes a leaf spring made from bonded laminated wood in which strips are bonded grain on grain and arranged along the axis of the leaf such that the grain of the wood is substantially parallel to the axis of the leaf spring and the bonding planes are perpendicular to the plane of the leaf spring.
HU-A-69569 describes a leaf spring made from wood in which a sprung slat is formed from a number of veneers glued together such that the thickness of the slat increases in the middle. The neutral zone of the sprung slat may incorporate a layer of at least one ply, which is thinner than the veneer strips and shorter than the sprung slat.
Examples of composite part-wooden laminates adapted to provide a combination of strength and resilience are disclosed by, inter alia, the following patent specifications:
JP-A-2001254476 describes a composite metal-wooden beam, the bending rigidity of the beam being reinforced by forming a composite in which a metal member, such as one or more metal wires, is integrated into a laminated wood material in which light and soft woods of low strength overlap in the fibre direction.
JP-A-4279332 describes a carbon fibre-reinforced laminated timber product in which at least one layer of the product comprises carbon fibre of a specified elasticity for the purpose of enabling use of the laminated material as a structural material.
Further examples of so-called “lift chairs” designed to assist individuals in rising from a seated position are described in the following specifications:
U.S. Pat. No. 4,690,457 discloses a lift chair in which a front portion of the seat is pivotally attached to the chair frame and a pneumatic cylinder is pivotally connected between a central frame member below the front portion of the seat and the seat.
U.S. Pat. No. 4,907,303 provides an orthopedic chair with a seat pivoted at the front to the frame of the chair. A spring mechanism biases the seat towards an upwardly pivoted orientation.
U.S. Pat. No. 4,729,598 describes a convalescent chair in which a seat support structure pivotally connected to the forward portion of the seat structure is elevated by a motorized jack from a horizontal position to an inclined position to assist in raising a patient from a seated position to a standing position.
U.S. Pat. No. 3,250,569 provides a chair having a seat elevator unit by which the seat is both raised and tilted forwardly to assist a person rising from the chair. The unit is removable and may be shifted from one chair to another.
The chair of GB-A-2183150 for use by an old or infirm occupant has a seat member that can be tilted about its front edge to slope downwardly and forwardly and is connected to a similarly pivoted armrest. The tilting is operable by the occupant.
Examples of similar vehicle seat arrangements for disabled drivers include the following:
GB-A-2191086 describes driving seat for a vehicle in which the door opening is at the front of the vehicle and the vehicle controls are on a retractable steering means. The driving seat is moved from the driving position to a forward entry/exit position and has a releasable compression spring for urging the squab of the seat upwards to assist the driver into a standing position.
GB-A-199698 provides a cushioned seat for vehicles which is pivotally mounted on a framework so that its rear end may be raised to assist the occupant in rising, following which the seat reverts to its normal position in which it is downwardly inclined towards the rear.